Ch.2 Anatomy & Glomerulus Flashcards
Which layer–medulla or cortex–is the vast majority of renal tissue?
The outer CORTEX
Where does the base of the Renal Pyramid originate? Where does the apex terminate?
base originates at the corticomedullary border….apex terminates at a papilla
Who is unipapillate? Who is multi papillate?
Humans=multi…rats/mice=uni
how many nephrons in a kidney?
1 million!!
How many cell layers make up the nephron?
One cell layer thick
Which tubules have the Brush Border on their luminal surface?
The PROXIMAL tubules have the brush border (the Distal do not)
What are the two principal populations of nephrons?
Coritcal and Juxta-medullary
Which nephrons are short looped and which are long looped?
Coritcal nephrons=short looped….Juxta-medullary=long looped
Which nephrons do not have a ‘thin’ ascending limb?
Cortial nephrons
Which nephron type composes the majority of the renal tissue? What % of nephrons are they?
Cortical Nephrons and they are 80% of the nephrons
What does the ratio of cortical:juxtamedullary nephrons tell us?
Ability to concentrate urine…more Jexta=more concentrated (rats have much more junta then us)
What is the subset of peritubular capillaries derived from EFFERENT Arterioles of JUXTAmedullary nephrons?
Vasa Recta ( ‘straight vessels’ in latin)
“________” orientation of the vasa recta parallel loops of Henle; play a critical role in maintaining the ________ of the renal medulla
“Hairpin-loop”…hypertonicity
What % of cardiac output do the kidneys receive? (in L?)
25% (1.2-1.5L/min)
Is oxygen consumption low or high? What does the A-V difference indicate?
VERY HIGH (almost as much as the heart)…A-V difference indicates that not much O2 is used, but it receives the most blood flow of any organ (4x)!
What is the 1st phase of the relationship between renal blood flow, renal O2 consumption, and Renal A-V O2 difference?
Decrease Renal Blood Flow=Decrease in renal O2 consumption=no change in A-V O2 difference.
What is the 2nd phase of the relationship between renal blood flow, renal O2 consumption, and Renal A-V O2 difference?
Flow from 150-75 ml/100g kidney= A-V O2 difference increases to maintain O2 comsumption
What is the 3rd phase of the relationship between renal blood flow, renal O2 consumption, and Renal A-V O2 difference?
Flow BELOW 75ml/100g kidney=A-V difference is at its MAX=Renal Ischemia
What happens to O2 consumption if we INCREASE RenalBloodFlow?
O2 consumption increases…need more O2 for the added work!
How much of the plasma entering the glomerular capillaries is filtered?
20%
What are the 3 principal components of renal function?
- Glomerular Filtration 2.Tubular Reabsorption 3.Tubular Secretion
Which of the 3 principal components of renal function is the principal mechanism for modifying the composition of the filtered fluid?
Tubular Reabsorption
Which of the 3 principal components of renal function is mostly restricted to solutes that are poorly filtered due to size/charge/or attached to a binding protein?
Tubular Secretion
Presence of proteins, glucose, amino acids etc. in the urine suggestive of ________.
impaired renal function
Urine ______ must be known to draw conclusions about excretory capacity.
flow rate (remember our example in class??)
Which muscle contracts as a result of the micturation process? What autonomic system is this?
detrusor muscle..parasympathectic activity
Which micturition abnormality is associated with spinal cord damage above the sacral region - loss of higher center control (particularly suppression) of the micturition reflex – periodic unintended bladder emptying?
‘Automatic Bladder’
Which micturition abnormality is associated with the loss of sensory nerve fibers – no micturition reflex therefore bladder overflows a few drops at a time – overflow incontinence?
A-tonic bladder
What are the 3 layers of the filtration barrier of the glomerulus?
1.endothelium(fenestrated) 2.basement membrane (collagen, etc.) 3.epithelium (podocytes)
What are the three components in the filtration slit in between podocyte foot processes?
Connectors, Linkers, and actin-cytoskeleton complex
Which cells provide structural support for capillaries, secrete extracellular matrix, possess phagocytic activity, secrete prostaglandins and cytokines, and possess contractile activity?
Mes-Angial Cells
If a molecule is above the 5000 Dalton threshold, what are the two deciding factors for filtration?
CHARGE and SIZE
What is the net charge of the filtration pathway? What is this governed by?
Negative…glycoproteins
What is the condition in which charge selectivity is LOST?
NeproToxic Serum Nephritis (NSN)
What are the 4 consequences of Proteinuria?
- Arteriole/venous thrombosis (loss of coagulants) 2.Infection( loss of Ig’s) 3.Hyperlipidemia (unknown origin) 4.Edema (decreased plasma oncotic pressure)
What are the forces involved in fluid exchange between plasma and intersitium?
STARLING Forces
What are the two Starling forces promoting movement out of the capillary?
Intracapillary HyrdoStatic Pressure and Intersitital Oncotic pressure
What are the two Starling forces promoting movement into the capillary?
Plasma oncotic pressure and tissue hydrostatic pressure
Which Starling force do we see ALL the change from the arteriole end to the veinous end thus promoting NET filtration?
BIG drop in Hydrostatic Pressure from Art to Vein ends. 40-> 15 (lymph gets the difference)
What are the three Starling Force factors that can lead to Edema?
1.Increase in Capillary Hydrostatic pressure c/o a vein blockage 2.Increase in Capillary Hydrostatic pressure due to inflammation 3.Increase in interstitial oncotic pressure lymph obstruction
Generalized edema involves ____ retention and expansion of the entire extracellular fluid volume… Commonly seen in cardiac, hepatic and renal failure.
Na+
What are the two areas causing resistance for blood pressure in the from the renal artery to the renal vein?
the afferent and efferent tubules
Why does hydrostatic pressure remain constant along the glomerular capillary?
Due to Resistant points BEFORE AND AFTER the glomerular capillaries
_____ progressively increases along the capillary
because as fluid is filtered out the concentration of non-filterable proteins increases
Glomerular Capillary Oncotic Pressure (protein aint filtered!)
What is the point where GC oncotic pressure and GC hydrostatic pressure equal?
NFP-Net Filtration Pressure
NFP similar in glomerular and systemic capillaries (10-20 mmHg), BUT the volume of fluid filtered across glomerular capillaries (180 L/day) is much greater than across systemic capillaries (approx 4L/day) because:
OF THE GLOMERULAR CAPILLARY ULTRAFILTRATION COEFFICIENT (much higher than in systemic capillaries) (c/o higher surface area and higher capillary amount) (more fluid=more filter)
What are the 2 determinants for the Glomerular Capillary Ultrafiltration Coefficient?
1.Hydrolic Water Permeability (capillaries are 100x leakier then systemic capillaries!) 2.Surface Area ( 2x more then skeletal muscle!)
Increase in Kf = ____ in GC oncotic P = NFP at an _____ point along the capillary
Increase in Kf=Increase in GC oncotic P = NFP at an earlier point along the capillary
What does decreased resistance in the Afferent Arteriole do to Glomerular Capillary Hydrostatic Pressure, GFR, and RPF?
P=increase…GFR=increase…RPF=increase
What does Increased resistance in the Afferent Arteriole do to Glomerular Capillary Hydrostatic Pressure, GFR, and RPF?
P=decrease…GFR=decrease…RPF=decrease
What does decreased resistance in the Efferent Arteriole do to Glomerular Capillary Hydrostatic Pressure, GFR, and RPF?
P=decrease…GFR=decrease….RPF=increase
What does Increased resistance in the Efferent Arteriole do to Glomerular Capillary Hydrostatic Pressure, GFR, and RPF?
P=increase…GFR=increase…RPF=decrease
GFR physiologically regulated primarily by changing resistance (diameter) of the _______ arteriole. What 2 ways does this happen?
Afferent…1.Sympathetic NS (vasoconstrictor) 2.Angiotensin II (MAJOR vasoconstrictor both afferent and efferent)
What are the major renal vasoDILATORS!!??
Prostaglandins (boost GFR!)
What happens to Renal vasoconstriction if BP decreases? What is fighting this process?
renal vasoconstriction increases….(increase in sym ns and angiotensin II)…both Sym and A-II increase prostaglandin syn=vasoDilation!
What would be the end result of a pt taking NSAIDs and then being stabbed?
Pre-Renal Acute Renal Failure…decrease in BP=increase in Sympathetic NS=Increase in Angiotensin II=increased vasoconstriction…WITHOUT opposition of prostaglandins(c/o NSAIDs!)
What are the three main alterations in GFR caused by?
1.Changes in Ultrafiltration Coefficent (Glomerular Disease, Mesangial Cell contracility) 2.Changes in capillary oncotic pressure (liver diease) 3.Changes in intratubular pressure (ureteral obstruction)
What is the protective mechanism that helps decrease GFR when there is a buildup of intratubular pressure (blockage)?
Ureter-o-renal reflex (ureter stretches and triggers the Sym NS to constrict the renal arterioles)
Why does BP not affect GFR?
AUTOREGULATION!
Autoregualtion: ______ ability of the kidney to maintain GFR (and renal plasma flow; RPF) constant over a wide range of blood pressure (~ ___ mmHg and above)…WHAT IS THE CONTROL SITE?
INTRINSIC…70 mmHg…afferent arteriole
What are the 2 proposed mechanisms for auto regulation? Which one does more work?
1.Myogenic 2.Tubulo-Glomerular Feedback Theory….TG does more work
TUBULOGLOMERULAR FEEDBACK THEORY: A change in flow rate/composition of tubular fluid sensed at the _______ causes a compensatory change in GFR.
MACULA DENSA (‘dense spot’ in latin)
What are the 3 set backs to auto regulation?
1.GFR and RPF only change slightly 2. Does not occur below 70mmHg BP 3.Can be overridden (stabbing/hemorrhage)
